The present invention relates to the field of motor vehicle fuel drawing devices comprising a filter.
Many filter arrangements have already been proposed for such fuel drawing devices.
Illustrated in FIG. 1 attached hereto is an example of an embodiment of a filter proposed by the Applicant company.
This FIG. 1 shows a filter element 10 placed in a plastic housing 20.
The filter element 10 possesses a filter body 12 of annular geometry made for example from a pleated piece of paper, arranged between two annular caps at its axial ends, one of which is the cap marked 14 in FIG. 1. Each of these caps 14 has a generally U-shaped cross section in which the concavity faces toward the filter body 12, and the web 15 possesses a drawn projection 16.
This filter element 10 is placed in an annular chamber 22 in the housing 20, and, as seen in FIG. 1, an elastomeric O-ring 30 is fitted between a step 24 formed on the wall of the housing 20 and the projection 16. This O-ring 30 is designed to prevent leaks between the cap 14 and the housing 20 so that the fuel cannot get around the filter. The fuel therefore passes radially through the filter body 12.
The structure illustrated in FIG. 1 may give satisfaction.
However, its operation is dependent on the presence of the O-ring 30, and if this is forgotten or incorrectly positioned, the filter 12 is useless.
The Applicant company has admittedly attempted to dispense with the O-ring 30 by adapting the positioning of the projection 16 and of the step 24 so that these would come into direct contact. However, these attempts did not prove satisfactory. Specifically, it is very difficult to prevent leaks satisfactorily around an annular surface of this kind between the step 24 and the projection 16.
Other solutions have been proposed in the literature. However, none gives complete satisfaction. Furthermore, as far as the Applicant company is aware, none of these proposed solutions has really reached an industrial production stage.
By way of non-exhaustive examples, the document DE-A-19718603 recommends the use of a zigzag elastic sealing structure, while documents DE-A-19711531 and DE-A-19646350 recommend sealing structures designed to be engaged/fitted onto opposing mating structures to prevent leaks by a labyrinth or equivalent effect.
The object of the present invention is to propose novel means to simplify filtration structures for motor vehicle fuel drawing assemblies.
This object is achieved in the context of the present invention with a drawing assembly comprising a housing possessing an annular chamber and a filter in said annular chamber, the assembly being characterized in that it comprises at least one annular plastic lip molded integrally on a part connected to the housing or to the filter, in a material capable of elastic deformation and shaped to form an oblique angle to the axis of the filter and of the housing chamber, in such a way that said lip rests, with elastic deformation, and at an angle with a tangential component via its free edge, against an opposite face, of the other of the filter or of the housing, arranged approximately transversely relative to the axis of the filter and of the housing chamber, in order to prevent leaks at this location between the filter and the housing.
In the context of the present invention, the annular lip is preferably molded integrally on a cap that fits on the filter.
Still more precisely, in the context of the present invention, the filter possesses an annular lip of this kind on each of its two end caps.